John,
are you using DTT which will cause the cobalt to turn brown?
Can you miss out the DTT during the IMAC step? Mike.
On Tue, 1 May 2001, John Eisses wrote:
> Bionetters,
> I am purifying a delicate membrane protein and imidazole seems to
> inhibit it, but when I use histidine, the Talon (Co2+) resin bleaches
> out and the buffer turns brown. Are there alternatives for imidazole? I
> seem to remember a ref for N acetyl Histidine , but does this strip the
> Talon resin? I'll try buffer exchange after the fact but I'd like to not
> lose activity as my experience is once its gone it doesn't come back.
>> salud
> Ted Michelini
>michelini at ohsu.edu>>